Water may be contaminated by organic and inorganic matter from various sources including domestic, municipal, industrial and agricultural sources. Contaminants may be in solution, colloidal or in suspension. Colloids, and in particular negatively-charged colloids, are often the predominant form in which water contaminants exist.
Electrocoagulation is an electrochemical method of treating water contaminated with various species in an electrocoagulation reactor having a cathode and a sacrificial anode. Supplying current to the electrodes causes the release of metal cations (usually iron or aluminum) from the sacrificial anode, and the formation of hydrogen gas at the cathode. Other chemical species may form which participate in a variety of processes that facilitate removal of contaminants from water.
The use of rotating electrodes has been proposed as one way to improve the remediation efficacy of systems using electrocoagulation. See, for example, Syversen et al., U.S. Pat. No. 6,099,703. Rotating the cathode helps to ensure even consumption of the sacrificial anode and inhibit fouling of the active surface of the cathode. However, despite developments in the art of electrocoagulation, most known electrocoagulation-based wastewater treatment systems are not capable of sufficient remediation of contaminated waters for subsequent release into the environment at an affordable cost or at the volumes necessary for full commercialization of large-scale treatment projects. The present invention provides improved apparatus and method for the bulk treatment of contaminated water.